With the continuously updated of modern science and technology, the rapid development of the domestic electric industry, and the increasingly competitive international market, the high/low voltage electrical equipments around the world emerge one after another. International Electrotechnical Commission promulgates a series of standards on electrical equipments, especially for the switching equipments of the electrical equipments, it requires controlling not only the testing voltage and current, but also the switching on phase angle and the breakover circle or waveform, as the testing voltage, testing current, and the switching on phase angle are the requirements for “short-circuit breaking and switching on/off capacity test” of the electrical equipments. The switching on/off phases of the switches within the current high and medium voltage systems are random, therefore the phenomenon of overvoltage and inrush current is very serious, and it cause a negative impact on the electric system operation and the performance of electrical equipments, the concrete embodiment as follows: shortenings the electrical equipment life, the insulation puncture and damage of the electrical equipment, the malfunction of relay protection, the malfunction of the quadratic electronic controlling component, and decreasing the electric power quality, etc.
In view of the above reasons, we give sufficient attention to the research and development of the switching on/off phase control of the switching equipment, and we consider that the research and development of the switching on/off phase control is the top priority for future research and development of the switching equipment.